Excerpts from Books and Wikipedia
The king of the Lombards was threatening to attack Rome. The Byzantines could not help, so the pope asked Peppin the Short for military aid. Pepin the Short and the pope met south of Paris. Later, Peppin the Short drove the Lombards from Ravenna and gave property to the pope. This was the beginning of the papal state. [Furtado: 1001 Days]